Electronic refrigeration control systems typically include defrost and temperature control capability. The systems precisely monitor and control (e.g., turn on and off) the compressor, evaporator fan, and defrost devices in response to user specified parameters, temperature, and time. Generally, the user may input user specified parameters by push buttons or keypads attached to the external housing of the refrigeration control system. The user can customize or program the control features of the refrigeration system via the user specified parameters. Additionally, electronic refrigeration control systems often include displays for providing indicia of the operating conditions of the refrigeration unit and time, as well as assisting in the input of user specified parameters.
The electronic refrigeration control system typically includes a control circuit coupled to a defrost relay, an evaporator fan relay, and a compressor relay. The defrost relay connects and disconnects power to a defrost device in response to a defrost control signal. The defrost device can be an electrical heater or a device for causing the compressor to operate in a reverse mode or "hot gas" mode. The evaporator fan relay connects and disconnects power to the evaporator fan in response to an evaporator fan control signal. The compressor relay connects and disconnects power to the compressor in response to a compressor control signal. Therefore, the electronic refrigeration control system manipulates the defrost device, evaporator fan, and compressor via a set of relay switches.
in a conventional electronic refrigeration control system, a control circuit and the various relays are contained in a plastic housing which is bracketed or otherwise mounted in the refrigeration unit. Alternatively, the housing may be a stand-alone unit. Conventional electronic refrigeration control systems utilize a single neutral return for the power provided to the electronic refrigeration control unit, as well as the neutral wire for the defrost relay, compressor relay and fan relay. Typically, the maintenance personnel must splice together all the neutral wires associated with the power input, defrost device, compressor, and evaporator fan, and connect a single neutral wire to the single neutral terminal or electronic refrigeration control housing.
Splicing several neutral wires together adds to the cost of manufacturing the refrigeration unit. Further, such a requirement reduces the reliability and increases the maintenance costs associated with the electronic refrigeration control system particularly when defrost units, compressors and evaporator fans are replaced. For example, if a evaporator fan is replaced, the neutral wire for the fan must be re-spliced with the neutral for the defrost unit and the compressor. Further, a single neutral terminal makes the connection of the fan, compressor and defrost unit more cumbersome and less accessible.
Therefore, there is a need for quick and efficient terminals which allow devices associated with the relays in an electronic refrigeration control system to be easily connected and disconnected without the need to splice neutral wires. Further, there is a need for an arrangement which allows neutral wires to be placed together to avoid short circuiting between hot wires associated with the power input, compressor relay, defrost relay, and fan relay. Further still, there is a need for multiple neutral terminals so neutral wires can be connected to the relays without splicing the neutral wires together from different relays.